Railway vehicle disc brakes

ABSTRACT

A railway vehicle bogie frame of the type in which longitudinal side members are movable about respective longitudinal rocking axis is provided with restraining means adapted to counterbalance the unbalanced weight of disc brake structure mounted on the side members. Restraint may be provided by spring means or rigid link means anchored between the side frame members and a bogie cross frame member or directly between the opposite side frame members.

United States Patent 1 Bannister Oct. 2, 1973 [54] RAILWAY VEHICLE DISC BRAKES 2,890,767 6/1959 Tack 188/59 7 4 62 1 Invem Robert Henry Arthur Bannister, $13339? 811364 2211? S2123 Tyseley, Birmingham England [73] Assignee: gIIIIgIIILIIEdLIIIIItQd, Birmingham, Primary Examiner Duane A Reger Att0mey-Scrivener et al. [22] Filed: July 7, 1971 [2|] App]. No.1 160,472 1 [57] ABSTRACT no] Forelgn Apphcanmi P Data A railway vehicle bogie frame of the type in which lon- July 8, l970 Great Br ta n 33,105/70 gitudinai side members are movable about respective Jan. 15, l97l Great Britain .u. 2,139/7l longitudinal rocking axis iS provided with restmining means adapted to counterbalance the unbalanced [52] [1.8. CI. 188/59, 188/206 R weight of i brake Structure mounted on the i [5 1] II Cl B6! 13/22 membei-S Restraint may be provided by spring means i 1 f'ff 188/33, 206 R or rigid link means anchored between the side frame members'and a bogie cross frame member or directly 1 References cued between the opposite side frame members.

UNITED STATES PATENTS 9 Claims, 10 Drawing Figures 2,692,659 10/1954 Tack 188/59 PATENTED 21915 3.762.506

,SHEET 2 BF '7' INVENTOR ATTORNEY PATENTED 2W5 I 3,762,506

SHEET 30F 7 I \W 7 l ['1 f I I cor-e.

0F BRAKE GEAR 1 X FIG-4 INVENTOR ATTORNEY SHEET Q 0F 7 PATENTEDUET 2 5 I \NVENTOR ATTORNEY PATENTEDBET 2% 3,762,506

SHEET 5 [IF 7 INVENTOR ATTORNEY PATENTED w 2 ms SHEET 6 BF 7 INVENTOR ATTORNEY PATENTEDUET 2 SHEET 7 BF 7 INVENTOR ATTORNEY RAILWAY VEHICLE DISC BRAKES This invention relatesto railway vehicle disc brakes. More particularly, the invention is concerned with railway vehicle bogie frames of the type having side members which are movable relative to one or more cross members about a generally longitudinal axis of the bogie, and in which brake structures are carried by these side frame members.

It is usual to employ tread type brakes, carried at the ends of the side frame members, but if disc brakes are required and the brake structures are mounted on the sides of the side frame members, the very substantial unbalanced weight of the brake structures causes the side frame members to tilt out of the vertical, and this in turn means that the disc brake pads are out of parallel with the brake discs, usually carried by bogie wheels, and taper wear of the pads will take place, reducing the useful life of the pads.

In accordance with a feature of the present invention this disadvantage is reduced or removed by providing restraining means acting on the side frame member to restrain it against tilting under the unbalanced weight of a discbrake structure.

The restraining means may, for example comprise tie-bar means acting between the side frame member and the bogie-frame cross member or between the opposite side frame members.

Alternatively, spring means may be arranged to provide a couple on the side frame member in opposition to that applied by the brake structure. A separate spring or springs may be provided for this purpose, or the suspension springs acting between the crossmember and each side frame member can be arranged to provide the required couple.

Some particular forms of bogie frames in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view ofa railway vehicle bogie frame to which the invention is applicable.

FIG. 2'shows an end cross section through a bogie frame taken between the disc brake unit and the wheels, and showing a form of restraining means according to the invention.

FIGS. 3 and 4 show an end cross section of a bogie frame taken in front ofthe cross member and each showing a different form of restraining means according to the invention.

FIGS. 5 and 6 show partial plan views of a bogie frame each having afurther different form of restraining means according to the invention.

FIG. 7 shows an end cross section through a bogie frame taken through the cross member, and showing another restraining means according to the invention.

FIG. 8 shows an end cross section through a bogie frame taken in front of the cross member, and showing a further restraining means according to the invention.

FIG. 9 is a front elevation of a bogie frame having yet another form of restraining means according to the invention.

FIG. 10 is a top plan view of the bogie frame of FIG. 9.

FIG. 1 shows a form of railway vehicle bogie frame currently in use, and which is normally fitted with tread brakes. The frame shown in FIG. 1 has been fitted with disc brakes. The bogie frame consists of two side frame members 10 and 11, two axles l2 and 13 each fitted with a pair of wheels and a cross member 14. The side frame members 10 and 11 are supported by the axles l2 and 13 and can both rock about their longitudinal axes. The cross member 14 is supported at either end by springs 15 acting between the side frame members and the cross member to provide a spring suspension for a carriage which is mounted upon the cross member 14.

Two disc brake structures in the form of units 16 and 17 are mounted on the side frame member 10 for braking the wheels on that side. Similar disc brake units may be mounted on the other side frame member 11 for braking the wheels on that side, or alternatively two disc brake units for braking two diagonally opposite wheels only may be used.

The disc brake units 16 and 17 have to be mounted on the inside of the side frame member 10 and consequentially provide an unbalanced load on the side frame member 10 tending to tilt the side frame member out of the vertical. This results in tapered wear on the brake pads and reduced brake pad life.

FIG. 2 illustrates one way of overcoming this out of balance force on the side frame member 10. A tension spring 18 is attached between a lower part of the disc brake unit 16 and the cross member 14 to provide a couple to counter balance the couple created by the disc brake unit 16.

FIG. 3 illustrates the use of a compression spring 19 for the same purpose mounted between the upper part of the side frame member l0-and a projection 20 on the cross member 14.

In FIG. 4 a tension spring 21 is mounted vertically between the cross member 14 and a lower part of the side frame member 10. The suspension springs acting on the side member 10 will produce a restoring couple to the side frame member when it tilts out of the vertical, and the magnitude of this restoring couple will increase with the loading .of the springs. Therefore, the more heavily laden the carriage the smaller is the restoring force required to be exerted by the spring 21. By mounting the spring 21 vertically and choosing a spring of appropriate rate, this condition can be satisfied so that the side frame member remains vertical however heavily the carriage is laden. With the arrangements of FIGS. 2 and 3 the springs 18 and 19 respectively are designed to compensate fully for the tilting when the carriage is fully laden, as it is then that greatest rate of brake wear occurs, as well as the greatest use of the carriages. I

In FIG. 5 correction for the tilting couple produced by the disc brake units 16 and 17 is provided by positioning the suspension springs 15 so that their centre line of action B is offset from the rocking axis A-A of the side member so that the spring 15 provide a couple counteracting the weight of the brake units.

In the arrangement shown in FIG. 6 the suspension springs 15 have different rates. Springs 23 on the inside of the centre line A-A are weaker than those 22 on the outside of the centre line. The springs 22 therefore provide a net couple. for compensating for the out of balance weight of the disc brake units 16 and 17. The springs 22 and 23 may have variable rates designed so that they provide exact compensation however heavily the carriage is loaded. I

In FIG. 7 compensation is provided by means of a bracing member in the form of a tie bar 24 pivotally attached to the bottom of the side frame member and the cross member 14. The tie bar 24 is sufficiently long so that the cross member 14 can move downwards with respect to theside frame member 10 as the carriage is loaded without causing any significant inwards pull on the side frame member 10. Since the side member 10 is held near the top by the rocking engagement with the axles 12 and 13 the side frame member 10 is prevented from rocking out of its vertical position by the tie bar 24.

In FIG. 8 a tie bar 25 pivotally connects the bottom of the two side frame members together without being attached to the cross member 14.

This provides a parallelogram arrangement and is most suitable when disc brake units are mounted on both sides of the bogie frame as the tilting action is compensated by the units on each side through the tie bar 25. Any tendency of the side frame members to tilt out of the vertical is resisted by the suspension springs 15 on both sides. The tie bar may have a screw threaded adjustment for adjusting its length as shown in FIG. 8.

The bogie frame of FIGS. 9 and 10 is similar to that of FIG. 8, the tie bar being replaced by a single leaf spring 26. The disc brake structures form convenient attachments for the ends of the single leaf spring 26, disposed in a vertical plane. The leaf spring acts as a tie bar between the side frame members which acts to resist tilting of the side frame members due to the out-ofbalance weights of the brake structures.

The spring can, however bow (in the horizontal plane) to permit relative longitudinal movement of the members 10 and 11 and can flex in torsion about its own longitudinal axis to permit relative angular movement, about a transverse horizontal axis, between the side frame members.

If the disc brake structures are not conveniently positioned to form attachments for the leaf spring (for example if they are diagonally opposed) a mounting bracket or brackets may be employed for attaching the leaf spring to the side member or members.

The spring is arranged, in the illustrated embodiment, to be stressed in tension by the unbalanced weights of the disc brake structures, but could alternatively be arranged for compressive loading.

I claim:

1. In a railway vehicle bogie frame having a cross member, a pair of side frame members which are movable relative to said cross member about a rocking axis extending generally longitudinally of the bogie frame,

suspension springs acting between said side members and said cross member and a disc brake structure mounted on one side of one of said side frame members thereby tending to tilt that side member out of the vertical, the improvement which comprises restraining means acting on that side frame member to restrain it against tilting under the unbalanced weight of said disc brake structure.

2. A bogie frame according to claim 1 wherein said restraining means comprises spring means arranged to apply a couple on the side frame on which said brake structure is mounted, in opposition to that applied by said brake structure.

3. A bogie frame according to claim 2 wherein said spring means comprises separate coil spring means acting between said cross member and said side frame member along a line of action transverse to the longitudinal direction of said side frame member and offset from the rocking axis of said side frame member.

4. A bogie frame according to claim 3 wherein said spring means comprises a coil tension spring arranged vertically and acting between said side frame member and said cross member, whereby the restraining force of said spring is reduced as the vehicle is loaded and said cross member towards said side frame members as said suspension springs compress.

5. A bogie frame according to claim 2 wherein said spring means comprise said vehicle suspension springs arranged with their centre line of action offset from the rocking axis of said side frame member so as to counteract the weight of said disc brake structure.

6. A bogie frame according to claim 5 wherein said suspension springs comprise coil compression springs of different springrates.

7. A bogie frame according to claim 1 wherein said restraining means comprise bracing means pivotally connected to said side frame member and to said cross member.

8. A bogie frame according to claim 1 including a disc brake structure mounted on the inner side of each side frame member, wherein said restraining means comprise bracing means connected between the two side frame members. i

9. A bogie frame according to claim 8 wherein said bracing means comprises a leaf springdisposcd in a transverse vertical plane, and capable of bowing in a horizontal plarie and twisting about its own major axis,

but which is rigid in the horizontal transverse direction. l k 8 

1. In a railway vehicle bogie frame having a cross member, a pair of side frame members which are movable relative to said cross member about a rocking axis extending generally longitudinally of the bogie frame, suspension springs acting between said side members and said cross member and a disc brake structure mounted on one side of one of said side frame members thereby tending to tilt that side member out of the vertical, the improvement which comprises restraining means acting on that side frame member to restrain it against tilting under the unbalanced weight of said disc brake structure.
 2. A bogie frame according to claim 1 wherein said restraining means comprises spring means arranged to apply a couple on the side frame on which said brake structure is mounted, in opposition to that applied by said brake structure.
 3. A bogie frame according to claim 2 wherein said spring means comprises separate coil spring means acting between said cross member and said side frame member along a line of action transverse to the longitudinal direction of said side frame member and offset from the rocking axis of said side frame member.
 4. A bogie frame according to claim 3 wherein said spring means comprises a coil tension spring arranged vertically and acting between said side frame member and said cross member, whereby the restraining force of said spring is reduced as the vehicle is loaded and said cross member towards said side frame members as said suspension springs compress.
 5. A bogie frame according to claim 2 wherein said spring means comprise said vehicle suspension springs arranged with their centre line of action offset from the rocking axis of said side frame member so as to counteract the weight of said disc brake structure.
 6. A bogie frame according to claim 5 wherein said suspension springs comprise coil compression springs of different spring rates.
 7. A bogie frame according to claim 1 wherein said restraining means comprise bracing means pivotally connected to said side frame member and to said cross member.
 8. A bogie frame according to claim 1 including a disc brake structure mounted on the inner side of each side frame member, wherein said restraiNing means comprise bracing means connected between the two side frame members.
 9. A bogie frame according to claim 8 wherein said bracing means comprises a leaf spring disposed in a transverse vertical plane and capable of bowing in a horizontal plane and twisting about its own major axis, but which is rigid in the horizontal transverse direction. 